Medical imaging is used extensively to diagnose and treat patients. A number of modalities are well known, such as Magnetic Resonance Imaging (MRI), Computed Tomography (CT), Positron Emission Tomography (PET), and Single Photon Emission Computed Tomography (SPECT). These modalities provide complementary diagnostic information. For example, PET and SPECT scans illustrate functional aspects of the organ or region being examined and allow metabolic measurements, but delineate the body structure relatively poorly. On the other hand, CT and MRI images provide excellent structural information about the body, but provide little functional information.
PET and SPECT are classified as “nuclear medicine” because they measure the emission of a radioactive material which has been injected into a patient. After the radioactive material, e.g., a radiopharmaceutical, is injected, it is absorbed by the blood or a particular organ of interest. The patient is then moved into the PET or SPECT detector which measures the emission of the radiopharmaceutical and creates an image from the characteristics of the detected emission.
A significant step in conducting a PET or SPECT scan is the step of acquiring the radiopharmaceutical. Examples of radiopharmaceuticals include FDG (2-[18F]-fluoro-2-deoxyglucose), 13N ammonia, 11C carbon, 15O gas, and 15O water.
The half lives of these radiopharmaceuticals range from two minutes to two hours. Thus, the injection into the patient and the imaging must take place within a very short time period after production of the radiopharmaceutical. Hospitals without the facilities to manufacture radiopharmaceuticals must order them to be delivered by ground or air transport from nearby manufacturing facilities, which can be very expensive.
In response to the growing practice of using nuclear medicine imaging, such as PET, many hospitals have built their own radiopharmaceutical manufacturing facilities. This option is also typically very expensive; however, due to certain requirements of the facility, such as the structure required to support the massive cyclotron, the air circulation system for the facility which cannot return air into the hospital space, and the shielding requirements arising from the radioactive nature of the radiopharmaceutical. Some hospitals have built separate structures to house radiopharmaceutical production. However, this option, while generally easier to achieve than converting existing hospital space, still requires extensive planning to satisfy all the structural, functional, legal, and regulatory requirements placed on radiopharmaceutical manufacturing facilities.
Accordingly, there is a need for a cost effective method for producing radioactive materials such as radiopharmaceuticals which may be implemented easily by organizations requiring them, such as hospitals and medical imaging practices.